Could a mixture be made up of only elements and no compounds?

The valence of aluminum is +3, and the valence of the chlorine is -1. the formula fir the aluminum chloride is correctly written as

At stp, which substance is the best conductor of electricity? a. nitrogen b. neon c. sulfur d. silver

Kp is the equilibrium constant for dissociation of the propionic acid dimer. what is the sign of the slope for a plot of the natural logarithm of kp vs. inverse temperature for this reaction?